1930s back extension work - how much? Experiences?

[SebbysMum]

We have a 1930s semi. It has a cheap extension on the back that will need replacing soon with something more integrated and permanent (permitted development) and then we'd like to knock through to turn the galley kitchen into part of a big family room. If losing the wall between existing kitchen and back reception we'll need some steel support I imagine.

I'm asking here as I know what we're doing is so common. So 2 questions - have you done this? And separately, cost of new kitchen aside, what do you think this could cost, ball park figure? We're in London

I guess it depends on if you want one big room or if you don't mind having some walls/columns? Also do you want steel concealed in ceiling or just boxed in? Any new bathrooms/utility? We had this done as part of whole house renovation so not sure about cost but at a guess 50-60k (London) including electrics and plumbing but without flooring and kitchen?

I have a 30s house and extended right across the back. The galley kitchen is now the utility room ( for washing/dishwashing machine, fridge/freezer, larder cupbaords etc) and I extended all along the back, opened up to the sitting room so it is now a big L-shaped kitchen/living room.
Cost - about £25k for the shell, not incl plastering, plumbing, electrics or flooring. Or the kitchen cupboards or appliances. (about £4k) Did most of it ourselves. Didn't need steels, as the room opens up from the double doors at the back, which had a lintel anyway. High, vaulted ceilings in new bit with 2 veluxes.

We're planning similar as part of whole house renovation. We're having a vertical steel support instead of steels across the ceiling.
Separating it from the other work we're doing I'd say 30k. South East, but not London.

Thanks. Also, we don't know whether or not we should engage an architect for this work and, if so, whether we're looking at a few hours of consultancy work or a pay for the project type involvement. Any thoughts?

I didn't want to pay for an architect - but I did get a draughtsman. He came round, drew the plans and submitted them to the council planning. ABout £500.

I did all the project managing - got quotes, got the builder, organised the plasterer, electrics, plumbing etc, but I've done it before

Some recent single storey flat roofed extensions I have designed have worked out at between 800 and 1800 per square metre - basic build cost - (sorry pound sign not working on laptop!!). Cheapest rate was rendered blockwork on ex-council house, top rate for stone and sloping site on listed building. South West rates.

My fees (architect) ranged from 650 to 2000 for survey, sketches, advice; and production of the building regs application drawing, which contains existing and proposed plans, elevations, site plan, location plan, basic section and notes.

Just to demonstrate that architects are not always expensive!

A builder could use this type of drawing to prepare an estimate but a full tender package including a specification would cost another 600 - 1000 or so.